The ETS Library was designed to optimize relevant search results on emissions trading systems by pooling together different information sources and classifying them according to categories tailored to the field. These categories are explained below. You can search using specific terms through the search bar, though you will find that most ETS-specific terminology is covered through the categories and that the library will return more precise results through the use of this built-in function.  To search a specific time range, simply enter the desired timeframe in the ‘YEAR FROM’ and ‘YEAR TO’ boxes.


There are four typologies under the “typology” heading that can be used to narrow down your search results: Systems, Design Topics, Effects, and Types of Information. Below is an explanation of each typology, its categories, and their sub-categories. First, the distinction and functionality of the categories and sub-categories is explained.

Level 1 and Level 2 variables

Each typology contains categories and sub-categories as variables for searches. These categories serve as level 1 variables, while their sub-categories serve as level 2 variables. Selecting the button next to the category will select both the category and the sub-categories, whereas pressing the name of the category or pressing the plus sign will display the sub-categories without preselecting them.

Some categories do not have further sub-categories, meaning that the level 2 variable will be the same as the level 1 variable.

What are the different typologies you can select?


The “systems” typology includes active, planned, previously considered, and cancelled ETSs as well as predecessors, non-GHG ETSs, and discussions and mechanisms that can be described as Global Carbon Markets. As mentioned above, some categories have sub-categories and some contain no further specification. If no system is selected in the search process, the ETS Library may suggest one in some cases to provide more accurate search results. Simply tick the box to include the additional category in the search.

Design Topics

The “design topics” typology draws largely from the design topics covered in the PMR & ICAP ETS Handbook. Each of the twelve categories is further divided into sub-categories to allow further specification. For example, if you are interested in allocation of allowances you can specify searches relating to auctioning, different types of free allocation methods, use of revenues, and other sub-categories.

Effects of ETS

The “effects” typology covers attributes of an ETS that are frequently studied. The categories are derived primarily from an ICAP paper on the benefits of ETS but also from other sources. These categories include cost-effectiveness, politics of ETS, greenhouse-gas abatement, and competitiveness and carbon leakage, to name a few. Some of the categories here are also divided into further sub-categories.

Types of Information

Under “types of information” you will find categories allowing you to separate results into legislation, policy recommendations, evidence and prediction papers, and policy history/descriptive papers.

Combinatorial Searches

It is possible to combine categories in your search. Combining categories will narrow down the search further, creating a logical AND function that returns results matching all categories selected. Combining sub-categories creates a logical OR function. However, searches combining sub-categories will prioritize results that match all selected sub-categories.

Media Selection

The ETS Library divides sources into three sections: articles, books, and everything else (other). Not specifying any of the sections will simply yield all types of sources.

Ordering the search results

On the bottom right of the parameter field you will find two buttons, ‘By date’ and ‘By relevance’. As a default, the library will sort by relevance, but there is also the possibility to sort by date, which gives the most recent results first.

Export in Dossier (“My Selection”)

With the ICAP ETS Library it is possible create your own dossier by exporting a chosen selection via a PDF or CSV file.

Ticking the box next to the title of a result will add the result to “My Selection”.


Clicking the ‘My Selection’ box will bring you to a different page where you will see your ticked entries, which can then be exported via the two export buttons in the top-right corner. Pressing back will return you to the library, but your selections will be saved. Deselecting the ticked box next to the article title in the ‘My Selections’ page will clear it from your saved choices.